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php

$this availability inside static-functions

php.internals

Sebastian Mendel

21 years ago

Hi,

at first, im really really sorry to bother the internals-list with this
problem (especially Derick for coming back from playing somewhere else
... (<Pine.LNX.4.62.0506291622130.14983@localhost>) ), but i didnt find
an answer on php.general or german php mailinglist

if anybody just can point me to any discussions, websites, bugs or
anything else related to the problem below. or just what is the point
behind this behaviour?


*PHP 4*

how can i check if a method is called statically when called from inside
another object? (without debug_bactrace())

class foo
{
function bar()
{
if ( isset( $this ) )
{
return 'not static';
}
return 'static';
}

function bar2() { foo::bar(); }
}


// returns 'static'
echo foo::bar();

// returns 'not static' but should be 'static'
$foo = new foo;
echo $foo->bar2();


*PHP 5*

and btw. does anyone know why it is not good to let one function handle
both methods of calling (static and not static) as in PHP 5 you will get
notices if called wrong - but PHP doesnt support multiple
function-definitions like:

class foo
{
static function bar()
{
return ANY_DEFAULT_VALUE;
}

function bar()
{
return $this->value;
}
}

or


class foo
{
static function bar( $param )
{
return $param;
}

function bar()
{
return $this->param;
}
}

--
Sebastian Mendel

www.sebastianmendel.de
www.sf.net/projects/phpdatetime | www.sf.net/projects/phptimesheet

Sean Coates

21 years ago

> how can i check if a method is called statically when called from inside
> another object? (without debug_bactrace())

<plug
type="own">http://blog.phpdoc.info/archives/4-Schizophrenic-Methods.html</plug>

Short answer:
$isStatic = !(isset($this) && get_class($this) == __CLASS__);

HTH

S

Sebastian Mendel

21 years ago

Sean Coates schrieb:

>> how can i check if a method is called statically when called from inside
>> another object? (without debug_bactrace())
>
> <plug
> type="own">http://blog.phpdoc.info/archives/4-Schizophrenic-Methods.html</plug>
>
> Short answer:
> $isStatic = !(isset($this) && get_class($this) == __CLASS__);

i know this hack, but it does not work, if the statically called method
is from the same class as the calling object

class foo
{
function bar()
{
if ( isset( $this ) && get_class( $this ) == __CLASS__ )
{
return 'not static';
}
return 'static';
}

function bar2() { return foo::bar(); }
}


// returns 'static'
echo foo::bar();

// returns 'not static' but should be 'static'
$foo = new foo;
echo $foo->bar2();

--
Sebastian Mendel

www.sebastianmendel.de www.warzonez.de www.tekkno4u.de www.nofetish.com
www.sf.net/projects/phpdatetime        www.sf.net/projects/phptimesheet

Sean Coates

21 years ago

> i know this hack, but it does not work, if the statically called method
> is from the same class as the calling object

Good point. Sorry for not noticing.
.. I have no idea WHY someone would want to do this.. that said, I don't
know of a way to do it, either.

S

Sebastian Mendel

21 years ago

Sean Coates wrote:

>> i know this hack, but it does not work, if the statically called method
>> is from the same class as the calling object
>
> Good point. Sorry for not noticing.
> ... I have no idea WHY someone would want to do this.. that said, I
> don't know of a way to do it, either.

a function who returns a name of an object, say its name is

$object->getName();

this needs that the object exists and loaded

how about if i need a name for object not loaded?

Class::getName( $object_id );

there is really no need to load/create the whole object if i only need
the name, so doing

$object = new Class( $object_id );
$object->getName();

would be a waste of system-resources

f.e. the same applies to any other properties of an object stored in a DB.

but why should i choose for the same function two different method-names?

f.e.

Class::getName()
static Class::staticGetName()

??

this doesnt makes sence to me.

pls, give me a hint if i had overseen something.

--
Sebastian Mendel

www.sebastianmendel.de
www.sf.net/projects/phpdatetime | www.sf.net/projects/phptimesheet

patrick müller

21 years ago

Sebastian Mendel wrote:

>
> how about if i need a name for object not loaded?
>
> Class::getName( $object_id );
>

Weird, i thought you must know the classname for a static
call :)

Sebastian Mendel

21 years ago

patrick müller wrote:

> Sebastian Mendel wrote:
>
>> how about if i need a name for object not loaded?
>>
>> Class::getName( $object_id );
>>
>
> Weird, i thought you must know the classname for a static
> call :)

not the classname, the objectname f.e. the name for the object of type
customer with id 31728 is 'Smith' ...

--
Sebastian Mendel

www.sebastianmendel.de
www.sf.net/projects/phpdatetime | www.sf.net/projects/phptimesheet

Andi Gutmans

21 years ago

I haven't quite understood what is wrong with instantiating the object.
After all, it most probably reflects some external data (or the name
wouldn't mean anything). Not creating the object itself won't save you
anything. Anyway, you can still do Foo::getName($object_id), if that
$object_id corresponds to some external resource like DB row.

Then again, I probably misunderstood you because I don't quite understand
the problem to begin with :)

Andi

At 08:59 AM 7/22/2005 +0200, Sebastian Mendel wrote:

Sebastian Mendel

21 years ago

Andi Gutmans wrote:

> I haven't quite understood what is wrong with instantiating the object.

i think its faster to just pull out the name (single value) from a
database than the whole object (row or even rows from different tables)

> After all, it most probably reflects some external data (or the name
> wouldn't mean anything). Not creating the object itself won't save you
> anything. Anyway, you can still do Foo::getName($object_id), if that
> $object_id corresponds to some external resource like DB row.

yes, but if someone calls Foo::getName() from inside an object who has
also the propertie $foo->name this function would return this
properties, but it should raise an user-error that there is missing a
parameter

of course, there is always a workaround - but why is $this available
inside a statically called method?

> Then again, I probably misunderstood you because I don't quite
> understand the problem to begin with :)

the main-question/problem is: "why is $this available inside a
statically called method?" (PHP 4)

and in PHP 5, the other point was, why should it not be possible to call
one method statically and not statically?



example, returning wrong $name:

<?php // PHP 4
class Foo
{
var $name = 'name_of_foo';

function getName()
{
if ( isset( $this ) )
{
return 'not static: ' . $this->name;
}
return 'static';
}

function getParentName()
{
return Foo::getName();
}
}


// returns 'static'
echo Foo::getName();

// returns 'not static' but should be 'static'
$foo = new Foo;
echo $foo->getParentName();
?>

> Andi
>
> At 08:59 AM 7/22/2005 +0200, Sebastian Mendel wrote:
>> Sean Coates wrote:
>> >> i know this hack, but it does not work, if the statically called
>> method
>> >> is from the same class as the calling object
>> >
>> > Good point. Sorry for not noticing.
>> > ... I have no idea WHY someone would want to do this.. that said, I
>> > don't know of a way to do it, either.
>>
>> a function who returns a name of an object, say its name is
>>
>> $object->getName();
>>
>> this needs that the object exists and loaded
>>
>> how about if i need a name for object not loaded?
>>
>> Class::getName( $object_id );
>>
>>
>> there is really no need to load/create the whole object if i only need
>> the name, so doing
>>
>> $object = new Class( $object_id );
>> $object->getName();
>>
>> would be a waste of system-resources
>>
>> f.e. the same applies to any other properties of an object stored in a
>> DB.
>>
>> but why should i choose for the same function two different method-names?
>>
>> f.e.
>>
>> Class::getName()
>> static Class::staticGetName()
>>
>> ??
>>
>> this doesnt makes sence to me.
>>
>> pls, give me a hint if i had overseen something.

--
Sebastian Mendel

www.sebastianmendel.de
www.sf.net/projects/phpdatetime | www.sf.net/projects/phptimesheet